Back Brake making noise - help!

[Yazzoo]

Just today I've noticed my back brake making a noise when applied, it's rhythmical as I go along, i.e. it's something on the wheel causing a routine noise each time it passes through the block under breaking.

Wheels appear fine to the naked eye, I did fall off this bike in the gravel last week but the noise has only started today.

Any ideas what it could be - apologies in advance, I'm not very mechanically minded, all I know is the noise is there but no sign of any damage/fault to cause it!

 

[sittingbull]

Make sure the blocks are clean, remove any grit embedded by drawing a wet cloth back and forth between the block and the rim. Ideally examine the block surface The rhythmical rubbing could be caused as any seam on the rim passes the blocks or if there are any kinks in the rim (pothole damage).

Make sure the blocks align with the rim when applied and do not overhang the tyre wall.

 

[Yazzoo]

Great, thanks, I'll have a thorough clean/check tomorrow

 

[Yellow Saddle]

A rhythmic noise and/or pulse as you described is to be found on the rim, not the blocks. Run your finger over the brake track on each side of the rim, feeling for dents or sharp burrs. Burrs can be sanded off, dents require psychological re-adjustment until you don't feel the pulse anymore. There's nothing other than replacing the rim that can fix that. As the red ox man above said, a rim seam can also cause a pulse. The seam is always directly opposite the valve. Nowadays the seams are welded and machined but seams of old weren't and always pulsed a bit. A small pulse is neither here nor there and should not stand in you way of riding to a nice pub for a beer.

 

[Mobytek]

get it trued for starters, maybe new rim, may be pulling it straight with a few nipple adjustments.

Once trued have the brake set up re adjusted.

Probs got a lump in your rim.

visiit your LBS

 

[Mobytek]

@User are you stalking me this morning .....?

 

[Yazzoo]

Thanks all, it's less than 2 months old, not ridden over any big potholes etc that I would have thought will cause it, will get it down and have a thorough look after work today, thanks for all your suggestions!

 

[TissoT]

Most likely to be the blocks as said above ..Take them off and rub them down with a nail file
also make sure the rim is clean

 

[jonny jeez]

Thanks all, it's less than 2 months old, not ridden over any big potholes etc that I would have thought will cause it, will get it down and have a thorough look after work today, thanks for all your suggestions!

When you take a look, hold the bike up and focus your eye on the brake block. As the rim passes the point where the pulse occurs, you should be able to isolate the offending seam/ding/dent as it passes the block. If you can't see anything, then maybe hold a thumb against the block so it touches the rim and "feel" your way round the rim

If you have not noticed a wobble in the rim then I second the possibility of a seam joint catching.

 

[Yellow Saddle]

Most likely to be the blocks as said above ..Take them off and rub them down with a nail file
also make sure the rim is clean

You own a nail file?